Neutrophil and monocyte migration and adherence to inflamed tissue are essential for normal immune function and are important components of early glomerulonephritis and acute renal allograft rejection. The leukocyte integrins, Mac-1 and p150,95, are essential for myelomonocytic cells to adhere to each other, to endothelial cells and to human mesangial cells. This binding function is regulated by cellular stimulation with chemoattractants or by phorbol esters; the second messengers involved remain to be defined. The goals of this project are to study the binding or avidity of Mac-1 and p150,95 after cellular stimulation and to characterize the tissue distribution of the ligands for both molecules. The strategy we will use will be to: 1) transfect human Mac-1 and p150,95 into mouse hybridoma T cell lines (some of which are deficient in second messenger production), 2) analyze changes in Mac-1 and p150.95 avidity in transfected cells after cellular stimulation and, 3) assess the binding of transfectants to human neutrophils/endothelial cells, cell matrix components and frozen tissue sections. The use of murine T cell hybridomas as transfectants will permit an analysis of integrin avidity change after cellular stimulation with antigen, and the use of hybridomas deficient in second messenger production will allow us to dissect the pathways involved in the change in integrin binding. In addition, interactions by other surface molecules that are species specific will be avoided by the use of mouse T-cell hybridomas.